Medication that must be mixed with a diluent before being intravenously administered to a patient is conventionally packaged so that the medication is stored separately from the diluent. One way of so storing medication is to seal it in a drug vial while separately storing the diluent in a flexible-walled container. When the medication is to be mixed with the diluent, a connector having oppositely-extending, intercommunicating, hollow spikes is attached to inlets of the drug vial and the container, so that the spikes penetrate pierceable stoppers in the inlets of the drug vial and the container. A portion of the diluent is then injected from the container into the drug vial by manually compressing the container, and, by pumping the container, the medication is withdrawn, along with the injected diluent, from the drug vial into the container and mixed with the balance of the diluent therein.
An alternative approach to separately storing medication and a diluent until the two are mixed, is to pre-attach, at the time of manufacture, a drug-injecting spike to the sealed inlet of a drug-containing vial. Such a pre-packaged assembly will typically be stored in a pharmacy as part of a stock of such assemblies containing other medications. Also stocked in such a pharmacy are sealed containers wherein are stored diluents of different compositions and amounts. Such diluent containers are typically flat, rectangular, flexible-walled pouches having a pair of openings along one edge. One opening serves as an inlet port, through which a drug may be drawn into the container as described, and the other serves as an outlet port, through which diluent mixed with the drug may be administered to a patient.
Some time (possibly exceeding a day) before a drug is to be administered, a request is placed for that drug and for a container having therein a diluent of the appropriate composition and amount. In filling the order, the pharmacist selects the appropriate drug dispenser and diluent container, removes a protective cap which covers the dispenser's spike, and inserts the spike through the pierceable stopper in the container's inlet port. Both in the case of the drug vial/diluent container which are coupled through a separate, double-spiked connector, and in the case of the drug dispenser in which the drug vial and the drug-injecting spike are pre-assembled, it is necessary, after the drug vial has been connected to the diluent container, to keep the contents of the drug vial and the diluent container separate, until just before the drug is to be intravenously administered to a patient. This is so because, once the drug and the diluent are mixed, the mixture's life is limited to a few hours. Therefore, while it is desirable to have an order for a particular drug/diluent combination filled several hours, perhaps even a day or more, before the drug is to be administered, it is in most cases mandatory that they not be intermixed until shortly before administration.
The object of the present invention is to provide a mechanism whereby the contents of a drug dispenser of the type comprising a drug vial with a pre-attached diluent spike may be kept isolated from the contents of a diluent container even after the dispenser's spike has been inserted in the diluent container, and to readily free a passage between the drug vial and the diluent container when it is desired to mix their contents.